Shock absorber for crutches

ABSTRACT

A device is provided for absorbing shock during use of crutches wherein are provided two telescopic tubes ( 6, 7 ) which, on the one hand, make possible adjusting the effective height of the crutch and, on the other hand, absorb the impact of the crutch to the ground. The device includes of a plug member ( 13 ) which is fitted to the upper extremity of the lower telescopic tube ( 6 ) and which has an elongate side hole ( 15 ) wherein a pin ( 11 ′) can slide and is secured to the upper external tube ( 7 ), precisely through an orifice ( 12 ) drilled in the tube. The length of the elongate orifice ( 15 ) of the plug member limits the relative motion between the two tubes ( 6, 7 ) forming the strut ( 1 ). The elements are maintained at a maximum distance from each other by a spring ( 10 ) positioned between the plug member ( 13 ) and the second pin ( 11 ) of the upper external tube.

PURPOSE OF THE INVENTION

This invention relates to a shock absorber for crutches. With it,crutches offer the best conditions regarding user's comfort through adamped support on the ground. The device has been conceived and arrangedin order to arrive at a considerable reduction in price of the crutch.

BACKGROUND OF THE INVENTION

Utility model number 9601865, from the same applicant, describes acrutch with which several problems and difficulties are solved. Thesederive from the frame-work or basic constitution of traditionalcrutches, whether they are finished off by a cross-piece made to beadapted to the armpit of the user, or they are those where the upper endis finished off by a semi-clamp to be adapted on its side to the arm,close to the user's elbow.

Therefore, in the utility model, the novelty of the crutch is describedas being the structure between the traditional cross-piece for thesupport of the user's hand, and the lower end for the support of thecrutch on the ground. The structure is characterized by a telescopicstrut, based on two sectors that are axially interconnected. So, thelower sector or span acts as a female element while the upper sector orspan acts as a female element while the upper sector or span acts as amale element, with the particularity that between both sectors or spansand internally, a bumper is placed to absorb the effects of the crutchimpact on the ground, when walking, and more precisely, the effects thatthe impact produce on the member which is holding it down and which istransmitting the corporal weight to it.

This solution avoids the typical “shock” at the upper extremities ofpeople using crutches to walk, which “shock” effect can producepathological irregularities in the individual, such as the so-called“crutch syndrome” and which is characterized by neurologicalirregularities in the arms, caused by the injury of the brachial plexuswhen passing through the armpit region.

Logically, structure characteristics of the crutch, which is the objectof the utility model 9601865, with regard to its telescopic capabilityand its bumper device incorporated by the lower strut of the crutchitself avoid or solve the troubles we just have explained.

Trying to improve the features of this kind of crutch, the applicanthimself is the holder of utility model 9700973 in which, starting from aconfiguration similar to the one of the utility model 9601865 previouslyquoted, it has been foreseen that the damping itself could be controlledas a result of providing a spring capable of being arranged so as tohave a larger or smaller degree of extensibility. Also, this damping canbe canceled without needing to pull out the spring but rather bychanging the position of a pin, which pin not only serves as a fixingpart for connecting the two pipes that constitute the lower strut of thecrutch, but also makes possible the damping because this pin is placedin a vertically extended window of the lower, internal pipe of the twopipes making up the lower strut of the crutch.

This solution, which is suitable from a functional point of view,represents in any case, an economical problem due to the costs forproviding the extended window in the pipe making up the strut.

DESCRIPTION OF THE INVENTION

The device proposed by the invention, starting from a performingphilosophy of the utility model 9700973, solves in a completelysatisfactory way, the troubles explained above as it makes unnecessaryany kind of machining in the pipe forming the strut.

For this and in a more concrete way, taking into consideration that itis necessary to “fit in” the upper end of that strut a cap provided withan axially upwardly extending rod to guide the spring that supplies thecrutch with the bumper effect, this invention is characterized byextending the body of the cap to enable establishment of the elongatedwindow or hole therein to absorb the telescopic motion of the strutagainst the elastic deformation of the spring, as well as a holenecessary to cancel the bumper effect through a position change of thecorresponding pin.

In this way and as it has been said above, the pipe forming the strutdoes not require any machining, and the part forming the cap, as it hasbeen obtained from plastic material and through injection, has a costnearly the same, with or without the holes. Therefore, the economicrepercussion that the presence of these parts represents, is no morethan the necessary material costs for its extension, and this materialcost is considerably lower than the former costs of the pipe machining.

DESCRIPTION OF THE DRAWINGS

In order to complete the description which is being made and with theaim of helping to a better understanding of the characteristics of theinvention, according to a preferable example of its practicalrealization, it is enclosed as an integral part of that description, aset of drawings where, on an illustrative and not restrictive basis, ithas been represented what follows:

FIG. 1 shows an exploded perspective view of a crutch provided with abumper device according to the present invention; and

FIG. 2 shows an enlarged detail and side elevation of the bumper deviceof this invention.

PREFERRED EMBODIMENT OF THE INVENTION

From these figures it can be observed that this crutch includes a lowerstrut (1), finished off at its end with a shoe or a non-slipping rubberplug (2), as a support element on the ground. The lower strut (1) isstraight and incorporates an upper cross-piece (3) for the support ofthe user's hand. From the cross-piece is extended a second span (orupper strut) (4) which is not very long and follows an oblique path withregard to the lower strut. This second span is finished off by a typicalsemi-clamp (5) adapted to receive the user's arm, close to this elbow.

The lower strut (1) is formed of two pipe sections (6) and (7)interconnected in a telescopic way, and the upper strut (4) is formed oftwo pipe sections (8) and (9), with the pipe (8) being the external oneand the pipe (9) being the internal one, but the former remaining in anupper disposition.

The two pipe sections (6) and (7) of the lower strut (1) telescopicallyslide between limit positions, against the stress of a spring (10)supported on the top by a pin (11), operatively established in one ofthe many holes (12) of the pipe (7), and supported on the other end by acap (or plug member) (13), connected to the upper end of the pipe (6)and provided with a rod or axial extension (14) serving as a guide forthat spring (10). A second pin (11′) holds together the two pipes (6)and (7) which make up the lower strut (1).

Starting from this basic and conventional structure, this inventionfocuses on how the pipe (6) is related to the pipe (7) by the pin (11′).As best seen in FIG. 2, the cap (13) incorporates a transverse,longitudinally elongated hole (15), in which the pin (11′) can slide,and a circular hole (16) in which the pin (11′) can be introduced whenit is desired to block relative telescoping movement of the two pipes(6) and (7) that make up the strut (1). In this way, the bumper effect(or shock-absorbing) can be eliminated without eliminating the spring(10).

In this way, the holes (15) and (16), which previously had to bemachined in the lower pipe (6), can be formed in the injection formationof the cap (13) itself, thereby realizing a reduction in costs.

It is not considered as necessary to make this description moreextensive in order that any expert in this matter could understand thisinvention and the advantages derived from it.

Materials, shape, size and positions of the elements could be changedwhen it will not represent an irregularity in the essence of thisinvention.

The terms used in this specification should always be taken in a broadand not restrictive sense.

What is claimed is:
 1. A shock absorber for a crutch having a lowerstrut formed of upper and lower telescopically connected pipes, theupper pipe having diametrical holes, a pin disposed in a selected one ofthe diametrical holes of the upper pipe, and a spring operativelysupported between the lower strut and the pin to provide shock absorbingduring telescopic movement of the lower pipe relative to the upper pipe,wherein said shock absorber comprises: a plug member attachable to a topend of the lower pipe and having an upwardly extending axial guide rodfor receiving the spring thereon, said plug having formed therein anaxially elongated hole and a non-axially elongated hole; and a lower pinmember selectively engageable in a shock-absorbing position in whichsaid lower pin member is fixed relative to the upper pipe and extendsinto said axially elongated hole of said plug member to allow playbetween said plug member and the upper pipe, and in anon-shock-absorbing position in which said lower pin member is fixedrelative to the upper pipe and extends into said non-axially elongatedhole of said plug member to prevent play between said plug member andthe upper pipe.
 2. A shock absorber according to claim 1, wherein saidlower pin member is selectively engageable in the diametrical holes ofthe upper pipe, such that, in said shock-absorbing position, said lowerpin member is engaged in one of the diametrical holes of the upper pipeand extends into said axially elongated hole of said plug member, and insaid non-shock-absorbing position, said lower pin member is engaged inone of the diametrical holes of the upper pipe and extends into saidnon-axially elongated hole of said plug member.
 3. A shock absorberaccording to claim 1, wherein said non-axially elongated hole is acircular hole.